Vacuum clutch control



, w40. P. E. MATTHEWS 2,208g133 VACUUM CLUTCH CONTROL Filed April 27, 1938 2 Sheets-Sheet l INVENTOR P/l Maf/flax ATTORNEYS my P E, MATTHEWS 2,208,133

VACUUM CLUTCH CONTROL Filed April 27, 1938 2 Sheets-Sheet 2 Patented July 16, 1.1940

seres VACUUM CLUTCH CONTROL Application April 27, 1938, Serial No. 204,555

s Claims.

This invention `relates to clutch actuating mechanisms and relates' particularly to devices for overcoming thewear on clutches of vehicles, `which is caused by slippage of the clutch elements during and after shifting gears, and during-normal operation of such vehicles.

One of the most common causes of premature v failure of clutches and clutch facings in vehicles ,is slippage of the clutch elements. Most Vclutches A'are provided with pressure exerting springs which urge the clutch elements into engagement with sufficient pressure to'preven't slippage. t The clutch pedal leverage, however, is related to the spring pressure so that the clutchpedal may be depressed `without* excessive eiort to disengage the elements when it is desired to stop the vehicle or to shift gears. Stated in another way, the effort required to release the clutch is not excessive, but the clutch elements are normally 2 forced 'so strongly into engagement that slippage between the elements is avoided. This nice balance of'clutchpressures and eiort to disengage the clutches is common to substantially all vehicle clutches and results in satisfactory operation, without slippage, so long as the clutch is properly manipulated. However, many drivers have the habit of allowing a foot to rest against the clutch pedal during normal driving. The slight pressure on the clutch pedal is sucient to 30*reduce the pressure which normally holds the clutch elements in engagement, and allows the clutch elements to slip.

Clutch' slippage and resulting Wear are even more common in large vehicles, particularly 35" trucks and busses of the rear motor type. The driver of such a vheavy vehicle cannot vget the feel of the shifting mechanism vand the relative speed of the motor and as a consequence aly 40' lows the clutch to slip during acceleration of the celerating large vehicles subjects the clutch facings to great friction and heat and quickly destroys them.

`45 The practice of allowing. the clutch to slip page by overcoming the decrease in pressure on the clutch elements which is caused by riding or exerting slight pressures on the clutch pedals.

5o 'g AV further object of the invention is to provide` lvehicle.4 The tremendous energy utilized in acwhich the objects of vthe invention are attained,

may include a booster element, which is rendered operative by actuation of the accelerator to such a vposition as `would ordinarily produce a low l' 7 motor speed and in response to actuation of the clutch pedal, to overcome a greater than normal resistance to disengagement of the clutch. In this form of the invention the clutch 'elements are normally forced into engagement by means of spring elements or other means with aconsiderably greater pressure than is normally used.

, or the leverage between the clutch pedal and the clutch actuating means is changed, so that a much greater pressure must be exerted on the clutch pedal than isnormally required to disengage the clutch elements. In order to overcome' this greater pressure or to' reduce the amount of effort required todisengage the clutch,

a booster element is provided which is responsive to movement of the clutch pedal and ofv the accelerator. Thus, `during gear shifting,`

,when the speed of the Imotor is reduced, the booster element becomes effective tol aid the operator of the vehicle in disengaging the clutch. During'periods of acceleration the booster ele-` ment is rendered ineffective and the amount of energy required to maintain the clutch pedal in a depressed position is greatly increased, thereby causing the operator to Irelease the pedal and 40 allow the clutch elements to engage. Likewise during normal cruising operation of the vehicle,

the booster element is" ineffective and the pressure exerted by riding the clutch will be insufcient to cause theclutch elements to slip. 45

For a better understanding of this invention, reference may be had-to the accompanying drawings, in which:

Figure` 1 is a diagrammatic showing of one form of the invention as applied to a rear motor type of vehicle; y f

Figure 2 is an `end View of one form of valve utilized in the invention;

Figure 3 is a View in section taken On line 3--3 ci Figure 2; and

Figure 4 is a vertical section of a solenoid -valve utilized in the embodiment of the invention disclosed in Figure l.

In Figure 1 of the drawings is illustrated a typical embodiment of the invention which includes a clutch pedal Iii, an accelerator pedal I2, a carburetor I4, and the transmission and clutch end of a motor I6, which may be situated or positionedat the rear end of a motor vehicle, the details of which are not shown, since they do not constitute the subject matter of the present invention.

The clutch pedal lll is providedwith a leve I8 which is connected by suitable links 20 and 22 to a lever 2li, which is fixedly connected to a clutch actuating yoke or arm 26. The yoke 26 bears against One of the clutch elements, whichy may be urged by means of springs or other equivalent constructions into engagement with the c0- operating clutch element. The springs utilized in forcing the clutch elements into engagement may have greater compression or tension strength than the springs normally used in the clutches of similar motor vehicles, or the leverage exerted by the clutch pedal lil upon the clutch yoke'may be varied so that a greater pressure must be exerted on the clutch pedal I6 than is normally required to disengage` the clutch'elements Typical forms of this invention which have been applied to motor vehicles have been so arranged that the pedal effort required to cause the clutch to begin to slip was raised from a normal of about 15 to 20 pounds to50 to 55 pounds and' the effort required to disengage the clutch completely was raised to 95 to 100 pounds. The increase in clutch pressure or eiort required to disengage the clutch may be variedr in accordance with the type of vehicle to which the device is to be applied.

Despite the desirable increase in clutch pressure, my invention allows the clutch pedal to bel depressed during the shifting .of gears with as,

responsive to movement of the accelerator pedal I2, and the intake manifold i2 of the carburetor I4. The arrangement of these parts is such that while the motor is idling or only slightly above idling speed the solenoid valve @Il is open, allowing the suctionefiec't of the intake gases at the carburetor to create a reduced pressure in the conduit 36. The valve 38 is normally closed when no pressure or only slight pressure is exerted on the clutch pedal. However, when the clutch pedal is depressed the valve 38 is opened and if the motor 'is idling or only slightly above idling speed, reduced pressure orv vacuum is created inthe booster cylinder 28, thereby drawing the piston 30 to the right, as viewed in vFigure 1, and aiding the operator of the vehicle to"disengage the clutch elements.

The action of the solenoid valve 40 is controlled by the yaccelerator pedal l2 so that depression or release of the pedal controlling the rate of operation of the motor directly controls the opening and closing of the solenoid valve 66. As shown in Figure 1, the accelerator pedal I2 is connected by a link llt to a bellcrank 46, pivotally mounted beneath the iioorboard of the vehicle. The bellcrank lever |6 is connected by means of a link 48 to the throttle valve controlling lever 50, in the usual way.

Mounted on the link 48 is an L-shaped arm 52, having a slotted free end portion 54 thereon. The kslotted end portion receives a pin 56, carried on a lever 68, which projects from a rotary or single pole switch 66. The switch B0 is provided with a pair of contacts 62 and 64, which are electrically connected to one terminal 66 of a storage battery 68 and one tapl0 of the solenoid coil valve 66. A switch 266, which may be the ignition switch for the motor, is connected between the terminals 66 and the tap 'it for breaking the electrical circuit between the solenoid and the storage battery when the vehicle is not inuse. The other terminal 'I2 of the storage battery and the other tap 'I4 of the solenoid of valve i0 are connected to ground. The slotted end portion 51| of the arm 52 allows suicient play or movement of the link i6 to permit slight acceleration o1 the vehicle without breaking the circuit between the storage battery 68 and the solenoid of valve 40. However, when the acceleration or the motor speed exceeds a certain predetermined value, the switch 60 is rotated to break the circuit between the storage battery 68 and the solenoid of valve 46, thereby allowing the valve'l to close.

One form of the valve 38 which is of known type, is illustrated in Figures 2 and 3. The valve 38 consists of a rigid generally cup-shaped casing 'i6 having a centrally disposed threaded bore 'I8 therein for receiving the threaded end 0i a bolt 82. Thebolt 82 is provided with an opkpositely directed threaded portion Sii, which may be threaded into link 22 and allows adjustment of the effective length of the link 22 after the fashion of a turn buckle. The casing 16 is provided with parallel conduits 86 and 88 which communicate with and are connected to the flexible conduits 34 and 35, respectively. The conduit or bore 8, is the inlet conduit and the bore 86 is the outlet conduit of this Valve. The inlet and outlet conduits 66 and 86 are disposed on opposite sides of an annular ring Sil, lwhich projects from the inner face o1" the casing 16 and cooperates with a diaphragm 92 to connect and disconnect the inlet and exhaust conduits 88 and B6; The diaphragm 92 is fixed to the peripheral face o1" the casing I6 and is retained thereagainst y by means of a shell 94 which is bolted thereto.

The shell 94 is provided with` a centrally disposed tubular portion 96 having a portion of restricted area 96 for receiving a shiftable, partly tubular rod mi). ternally threaded portion |02 which receives a bolt |64 having oppositely directed threaded ends |66, |63 and which, like bolt 82, allow adjust ment of the effective length of the link 20. 'Ihe opposite end of'the rod |66 is provided with a bore I |23 having a threaded portion I I2 at its outer end. The threaded portion I I2 engages a tubular element H4 which projects from the center portion oi' a disk member Iii, having an annular concentric depression IIE. The disk member I|8 and tubular member Il@ are slidably mounted on a stud |26, which projects from the center of the casing 76. The stud |20 may be provided with oil grooves |22 and has alreduced threaded portionY |265 at its outer end for receiving a cylindrical nut |26 of greater diameter than the internal diameter of thetubular lmember |I4, but closely fitting the bore l I0 of rod |00. The length The rod it!) is provided with an in.

2,208,133 of the stud |20 is greater than the length of the.

tubular member I |4, thereby allowing the tubular member and theconnected rod and link 20 to move a shortdistance relativelypto the casing 16.l f l `The movement of 4the rod |00 relative to` the casing 10 is utilized to make and break communication between the inlet and outlet conduits S8 and,86. The diaphragm `92 is provided with a central aperture through which the sleeve ||4 outlet or exhaust conduit 86.

Normally' the diaphragm is urged tothe left, as viewed in Figure 3, by means of a. spring |30,

whichbears against'the central portion of the disk |26 and the restricted portion 98 of the sleeve et, thereby urging the diaphragm against the 'ring 90 and allows direct communication of the inlet conduit 88 with the outlet conduit 86. At

the same time the disk |6, by coming into abutl ment with the diaphragm at a` zone outside the apertures |28,` seals the apertures |28 against communication with the atmosphere and allows the pressure reductiony created by passageof air through the intake manifold 42 of the carburetor to reduce the pressure in the booster 26,. if `the solenoid valve 40 is open. When the clutch pedal is depressed further the whole valve 38\moves with the links and 22, acting-as a connector between them to aid in moving the lever 24 for releasing the clutch.

When the clutch pedal I0 is released the spring forces the diaphragm tov the left breaking communication between the inlet and outlet conduits and 86, respectively, and the disk ||6 moves out of 'engagement with the diaphragm 92, thereby allowing air to pass from the outside of the device, through the'apertures |28 and |29,

in the diaphragm 92 and disk |26, respectively,

' M0 in the shell 94. The casing |32 may also be provided with a gasket |42 between the rod |00 and the casing, thereby preventing dust or other material from entering the interior of the valve.

The solenoid valve which isof known type is best shown in Figure 4 and may consist` of a metallic valve casing |44 having a. longitudinal passage |46 therein, which may be connectedin any suitable way to the eXible conduit 35. A transverse or right angle passage' |40 is formed inthe valve casing and' communicates with the longitudinal passage |46 In alignment with but on the yopposite side of the casing from the passage |48 is mounted a solenoid lthaving an armature |52 slidable therein and normally urged towardthe passage |48 by means of a spring |54 engaging the end of the armature. The arma--` ture |52 is provided with a reduced neck' |56 which passes through a restricted'but rgreater diameter aperture |58 in a valve seat |60, the valve seat being disposed adjacent the longitudinal passage |46. The valve seat-|60 is provided with spaced ilange |62 having an-aperture therein for receiving a portion of the armature |52 and providing a space through whichv air `may be drawn through the aperture |58 into the longitudinal passage |40. A similarvalve seat |64 is disposed in alignment with the valve seat |60 but on the opposite side of thelongitudinal passage |46. The valve seat |6f is provided with an aperture which communicates with an enlarged chamber |66 atthe inner end of the transverse passage M8.v The chamber |68 is closed by means of a plug |12 having a castellated upper end |12 and ari-.internally threaded portion |14 for receiving a coupling |16, which is connected to the conduit 36.

The reduced portion `|56 of the armature |52 carries'a valve plug |18, preferably made of rubber, which may be brought into a sealing relationship with either of the valve seats |60 andI |64. The chamber |69 contains a disk valve |80 which may also seal theaperture in the valve seat |64 under certain circumstances. The left hand end of the valve casing |44, as viewed in Figure 4, may loe-provided with a removable plug |82 having a breather aperture |84 therein, which permits the communication between the outside atmosphere and the longitudinal passage' |46 when the valve |13 is-in its lower or closed position. The plug |82 may be provided with a cap |86 having its periphery spaced from, the periphery of the plug and which acts to preventthe entry of foreign material into the valve 4l).

In operation when the accelerator pedal I2 is in its upper or idling position, the switch 60 is closed, completing the circuit through the stor` age battery and, the solenoid valve 40, energizing the solenoid |50 and moving the armature I 52 with the valve plug |18'into its uppermost position. The position of the valve plu g |18, there-` fore, is such as to allow direct communication between the intake manifold 42 and the valve 38. l

far enough tocause switch to break the circuit between the storage batteryv 68 and the solenoid valve 40, the spring |54 forces the: armature |52 downwardly and thevalve plug |18 into engagement with the valve seat |64, thereby breaking the connection or sealing the intake-manifold of the carburetor from the valve 38. rihe valve plug |18` at thel same time clears the valve seat |60 and allows communication between the outside air through the greather aperture |84 and the valve 30. In the event of a backnre through the carburetor, the disk valve |00 will be blown upwardly from the castellated portion |12 against the underside of the valve seat |80 and Will prevent damage to any oli the parts communicating therewith. y f

By proper regulation of Ithe booster device 26, the actual clutch actuating pressures during gear shifting and while the motor is idling may be reduced well below those normally required to actuate the clutch and at the same time will allow the use of greater clutch pressures during normal operation of the vehicle. that a simple yet eiective mechanism has been produced for overcoming the wear of clutches, which results from clutch slippage. It will be understood, ofcourse, that the relationship and construction of the parts may be varied, as desired, andv other types of valves and booster mechanisms may be used in the place of those specifically illustrated ywithout departing fromr the invention.

The above described embodiment of the invention should therefore be considered as illustrative, only, and not as limiting the scope of the following claims.

I claim:

, l. A device for reducing' clutch slippage in vehicles having a motor, a clutch and a member for controlling the speed of the. motor, comprising manually actuated means for releasing the clutch, booster means for supplying additionalV energy for releasing said clutch and means operatively vconnected to the member and the manually actuated means 'rendering the booster means effective when the member is in a position normally causing the motor to operate at low speed and the means for releasing the clutch is actuated.'v f

2. In a. device for reducing clutch slippage in vehicles having a motor, a clutch and a member for controlling the speed of operation of themotor, .the combination of manually actuated means for releasing the clutch, iuid actuated boostermeans for supplying additional energy for releasing the clutch, and valve means for rendering said booster means eiective and ineffective actuated by the member and the means for releasing the clutch to render the booster means ineffective when the member is in a position normally causing the motor to operate at high speed.v

3. In a device for reducing clutchl slippage in vehicles having a motor, a clutch and a member for controlling the speed of operation of the motor, the combination of manually actuated means for releasing the clutch, uid actuated booster means for supplying additional energy for releasing the clutch, and valve means for rendering said booster means eective and ineffective actuated by the member and the means for releasing the clutch to render the booster means effective when the member is in alposition normally causing the motor to operate at low speed and the means for releasing the clutch is actuated. I

4. In a device for reducing clutcn slippage in vvehicles having a motor, a clutch and a member It will thus be seenl ing the motor tooperateat high speed and effective-when the member is in a-positionnormally causing the motor toioperateat'low speed and the means for .releasingthe clutchis actuated.`

5. In a device for reducing clutch slippage n vehiclesshaving a motor, a clutchand va member for'releasing the clutch' and means movable between lowy and high speed positions for controlling the speed' of operation of the motor, the combinationwith 2 the clutch -releasing member of a vacuum/actuated booster operatively connected to andfor` facilitating the release of the clutch, Vacuum producing means associated with the booster, and means actuated by the motor control means and the clutch releasingm'ember for connecting the vacuum producing `means tothe means actuated by'themo'to-r control means and the clutch releasing'meana comprise a solenoid valve electrically actuated in response to movement of the motor -control means, and a da. phragm valve actuated in response to movement of the clutch releasing means.

-7. Inv a clutch releasing device for motor vehicles-having an accelerator, the combination with a clutch of booster means for aiding in releasing theclutch, means for energizing the' boostenar member for `manually releasing the clutch, vmeans connectingsaid member to the clutch comprising a valve operatively connected to the'booster means `and the 1'means for energizing thev booster and having cooperating elements for allowing communication between the booster and the energizing means when the member is actuated to release the clutch, and a solenoid valve operativelyconnectedy to the booster means and the meansfor energizing the booster meanaineans 'actuated Vby the accelerator for rendering thel solenoid valveoperative to allow and prevent communication between .the booster meansfand the means for energizing the booster means. l

8. In a device vfor reducing clutch slippage in vehicleshaving a motor, movable means for controlling the rate of operation yoi? the motor, a clutch and a manuallyA operated member for releasing' the clutch; the combination with the clutch releasing member and the means for controlling the rate ofthe operation` of the motor `of vacuum operated-boosteroperatively connected to and for facilitating the release of the clutch, vacuum producing Imeans for actuating said booster, means interposed betweenvsaidfbooster and said vacuum producing means for controlling operationfof said booster comprising a normally closed valve associated with and opened by actuation of the clutch vreleasing member, a solenoid valve, afsource ofelectrical energy, a switch for electrically connecting said source to and disconnecting saidsource from saidr solenoid valve, said solenoid valve being open when said switchis closed and closed when said switch is open, and

means connecting said switch to the motor controlling means for opening said switch when the motor vcontrol means is moved beyond a predetermined point. l

, `PHILIP E. MATTHEWS. 

